I Knew They Were Something Special

[toddalin]

When I acquired my Super Reds with the electronic crossover and eq units, I knew they were something special (rare) but could find no information on them. Someone saw them on AudioKarma and rememberd an old magazine article mentioning them. Apparently there were 30-40 of these time aligned electronic "Time Sync" crossovers made for use with the Super Reds. They were made by AudioTechniques.

https://lens.google.com/search?p=ASQ0Rg1A_bD7zKHMgxNmiUtJHkqO_ar8dIKEXAxz6 U3UR62awlbMlyuGEdLgQ8ssDaC5tU15LRFpvwaCuQMXBFspH3R-9zM8j3K5crtzYkW7y4UR5B1-UEPI1-I3Az4lqAlpbvU0e4yZyZU4an85C7Bp0CWLq24lGPzwd_fN28y2 mH4JtYDhN2I0PBeDjTbWgIud6VjhPCD7dTUAd-kbd9mhdbPwFKohwB4ARe2urVuZXQOmAT84CZnch0--tVuqh9sRMMy764CJT2r89_pG1koJGDls6AEkNfpOXUvn3Ii9es RGR06H2FUTHLY60n8tEvLfNZJYYIZ3ejotC7ppRm-e6A%3D%3D&s&ep=ccm#lns=W251bGwsbnVsbCxudWxsLG51bGwsbnVsbCxudWx sLG51bGwsIkVpWUtKR0k1WkdWaU1XUXdMV1UwT1RFdE5Ea3daU zA1TlRWbExXWm1NV1JpWkRNMk1URmhPUT09Il0=
https://lens.google.com/search?p=ASQ0Rg1A_bD7zKHMgxNmiUtJHkqO_ar8dIKEXAxz6 U3UR62awlbMlyuGEdLgQ8ssDaC5tU15LRFpvwaCuQMXBFspH3R-9zM8j3K5crtzYkW7y4UR5B1-UEPI1-I3Az4lqAlpbvU0e4yZyZU4an85C7Bp0CWLq24lGPzwd_fN28y2 mH4JtYDhN2I0PBeDjTbWgIud6VjhPCD7dTUAd-kbd9mhdbPwFKohwB4ARe2urVuZXQOmAT84CZnch0--tVuqh9sRMMy764CJT2r89_pG1koJGDls6AEkNfpOXUvn3Ii9es RGR06H2FUTHLY60n8tEvLfNZJYYIZ3ejotC7ppRm-e6A%3D%3D&s&ep=ccm#lns=W251bGwsbnVsbCxudWxsLG51bGwsbnVsbCxudWx sLG51bGwsIkVpWUtKR0k1WkdWaU1XUXdMV1UwT1RFdE5Ea3daU zA1TlRWbExXWm1NV1JpWkRNMk1URmhPUT09Il0=

https://www.audiokarma.org/forums/index.php?attachments/screenshot_20220221-020107_adobe-acrobat-jpg.2491475/

https://worldradiohistory.com/Archive-All-Audio/Archive-DB-Magazine/80s/DB-1982-08.pdf

[toddalin]

Not a Time Sync. Mine does much more.


https://worldradiohistory.com/Archive-All-Audio/Archive-Recording-Engineer/80s/Recording-1980-06.pdf (http://Well, did more research, and it is not a Time Sync.It does much more than a Time Sync.https://worldradiohistory.com/Archive-All-Audio/Archive-Recording-Engineer/80s/Recording-1980-06.pdf)https://worldradiohistory.com/Archive-All-Audio/Archive-Recording-Engineer/80s/Recording-1980-06.pdf

[BMWCCA]

Not a Time Sync. Mine does much more.


https://worldradiohistory.com/Archive-All-Audio/Archive-Recording-Engineer/80s/Recording-1980-06.pdf (http://Well, did more research, and it is not a Time Sync.It does much more than a Time Sync.https://worldradiohistory.com/Archive-All-Audio/Archive-Recording-Engineer/80s/Recording-1980-06.pdf)https://worldradiohistory.com/Archive-All-Audio/Archive-Recording-Engineer/80s/Recording-1980-06.pdf
Dead link

Clip and this is what I got: https://worldradiohistory.com/Archive-All-Audio/Archive-Recording-Engineer/80s/Recording-1980-06.pdf

[Robh3606]

Great articles! Nice history on the 604! Have to edit it and get it into the Library.

Rob :)

[grumpy]

A fun read. Thanks Todd. Good job saving those from the crusher!! and that you found out more about their place in 604 history (as Rob said :)).
Did seem like there had to be more to these :thmbsup:

[toddalin]

Dead link

Clip and this is what I got: https://worldradiohistory.com/Archive-All-Audio/Archive-Recording-Engineer/80s/Recording-1980-06.pdf

Thanks.

My crossover looks nothing like the one AudioTechniques sold and shown on pages 115 and 117.

https://cimg3.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/800x531/80-dsc_000614_4a65a748afc720cb0b93c0b7c4e5f52f4a01435 f.jpg

[Ian Mackenzie]

l recall hearing them at Todd’s.

A great story.

It confirms three things to me.

Listening to the original 604 dual concentric design does drive you crazy as confirmed by Doug Sax. That in those days acclimation was more important to studio users than absolute accuracy. What ever large monitors got in the recording industry back then stayed in due to the need for consistency.

In comparison it’s interesting that multi way loudspeakers were all the fad in the consumer hifi market place from the 1970’s right up the present. Very few brands promoted time aligned loudspeaker in the Ads. Some brands used stepped baffles to align loudspeaker drivers.

I tend to agree that time alignment was/is only discernible on certain kinds of program material.

What we do know is that driver voice coil offset can impact on the smoothness of the frequency response in the vertical domain. If you stand up and listen it will sound tonally different to sitting down. This is due to differences in path distances caused by geometry angles which causes phase cancellation in the crossover region. This also applies to dual concentric loudspeakers.

Time alignment can only be accomplished on axis with dynamic drivers.

My preference is a loudspeaker that is fundamentally accurate with discernible few time alignment flaws over a loudspeaker that compromises absolute accuracy for exact time alignment.

I don’t think any can argue the point on that but this could end up a very long thread.

Bring it on……Lol.

[rusty jefferson]

...My preference is a loudspeaker that is fundamentally accurate with discernible few time alignment flaws over a loudspeaker that compromises absolute accuracy for exact time alignment...

Well, that's a broad brushstroke. I'll narrow it down by saying you can't have absolute accuracy without nearly perfect accuracy in the time domain. Maybe that can't be argued with? ;-)

[Mr. Widget]

Well, that's a broad brushstroke. I'll narrow it down by saying you can't have absolute accuracy without nearly perfect accuracy in the time domain. Maybe that can't be argued with? ;-)I’ll narrow it down further. You can’t have absolute accuracy. Period.

That said, I think it is obvious that absolute accuracy is not needed for musical enjoyment.


Widget

[gasfan]

No, but the pursuit of it is. :)

[Robh3606]

My preference is a loudspeaker that is fundamentally accurate with discernible few time alignment flaws over a loudspeaker that compromises absolute accuracy for exact time alignment.

I don’t think any can argue the point on that but this could end up a very long thread.

Bring it on……Lol.


I agree as well. Time alignment and phase coherence are greatly overrated. Frequency domain is much more important.

Rob :)

[Mr. Widget]

I agree as well. Time alignment and phase coherence are greatly overrated. Frequency domain is much more important.

Rob :)+1

The stepped baffles, staggered arrays, "time coherent" crossovers, and even the rounded corners of the past while not irrelevant are really only the last 10%... you gotta get the 90% right first!


Widget

[Ian Mackenzie]

Hi Rob,


Altec 604
Looking at the 604 design it’s kind of odd that Altec either had their heads in the sand or perhaps were playing it safe and decided to keep the 604 as the original.

At the time DB Keele Jnr had involvement with Altec’s manta ray horns and then worked on JBL’s bi radial horn for the 4430/4435.

I am wondering why Altec did not leverage Keele’s horn design expertise in developing the 604 to maintain its position in the market?

Around the late 1970’s to early 80’s Altec re-launched its brand into consumer hifi with the model 19 as the flagship, the model 17 (604 design) and the smaller systems. I heard them all at a demonstration arranged by the distributor. It’s was all about a big reverberant sound. At that point in time (pre cd red book) it was impressive but l personally felt that the bass was lacking.

More recently Great Plains Audio have picked up the 604 and made an attempt to offer an iteration but l am unaware of how far they went on R&D to improve it or just a different take on the 604?

Perhaps someone can chime in with any relevant information on the Great Plains 604.

Kef Uni-Q
Interestingly Kef’s head of acoustics now with Kef for 15 years has made significant R&D advances into the Kef Uni-Q dual concentric driver HF lens/wave guide. In a YouTube he explains how how the planar action of the HF diaphragm is converted into a wave squeezing action via a mathematically derived waveguide/acoustic lens. The outer mid cone then continues the development of the wave front.

The Hi end variant of the Uni-Q driver used in the Kef Blade and reference series has a very large voice coil that is terminated mid way from the centre of the mid range diaphragm to the surround. Kef R&R has engineered a special lossy plastic decoupling to terminate the voice coil to the metal diaphragm. The lossy coupling is activated at frequencies above the crossover point forming an acoustic low pass filter. This effectively suppresses high order break up resonances from the metal mid range diaphragm by attenuation of high frequency vibrations.

Pretty clever engineering. The driver is a work of art.

https://m.youtube.com/watch?v=mR1m0U4xZvY

https://m.youtube.com/watch?v=9Lij_9adOYE

R&R from Kef’s sister company Celestion is shared with both businesses.

https://celestion.com/products/?fwp_product_catalogue=axiperiodic-drivers

https://celestion.com/key-technologies/


Other coaxial driver manufacturers
Over at Radian they are mounting Ribbon drivers into their coaxial driver units as s as n alternative to compression drivers. Their co axial driver are relatively affordable for us audio amateurs.

RCF and others also make very good coaxial drivers in various sizes available from

https://usspeaker.com/homepage.htm

I thought this might be of interest to the thinking cap type of audio amateurs who like to seek out new approaches to sound re production. I do not believe that a high quality coaxial driver is an exclusive design and nor should it be expensive. An interesting project for the audio amateurs. These other manufacturers have improved these coaxial designs in recent times. They have received good reviews on Voice Coil an industry journal. If interested l would be looking at the aluminium or titanium version over the exotic beryllium until you get an idea of what they can do. Radian would be my pick but l would also look at the others.

As a side note while the top Kef system are expensive the key tech is engineered to lower price points.

[Ducatista47]

I’ll narrow it down further. You can’t have absolute accuracy. Period.

That said, I think it is obvious that absolute accuracy is not needed for musical enjoyment.

Widget
I could not agree more, I enjoy listening to 1930s recordings if the music is great.

Even so, I continue to be let down over how few music enthusiasts seek reproduction that attempts to follow as closely as possible what went into the microphone. You know, what the musicians actually did. As I have said before, it seems everyone has their favorite distortion; euphonics is the biggest flavor in high end audio. I have passed the point where speakers can come close enough to the truth to compete with what a modest personal listening system can do, so I have nothing to contribute anymore to speaker discussions. But I still like to hear what you guys have to say and report about it.

Since we now actually know how to record accurately and create media (streaming included) for home use that reflects that result, I do find it strange how much money and toil one will put into improving speakers, which will still have a couple of orders of magnitude more distortion than the electronics that drive them and at least another order of magnitude worse than the source material. If one is chasing perfection speakers are not a fitting tool to do it with. Playing music euphonically should not cost much. Simply accepting the shortcomings of the tools we enjoy anyway seems a more rewarding path than dwelling on the ways we wish they were better.

Remembering the vinyl era, we ancient ones often have to explain that we didn't even hear the pops and cracks. We learned to ignore them. Speakers are like that, if we let them be. Our brains know what music sounds like and it does a fine job of filling in the blanks both speakers and listening rooms get wrong, and tweaking towards reality.

[Ian Mackenzie]

+1

The stepped baffles, staggered arrays, "time coherent" crossovers, and even the rounded corners of the past while not irrelevant are really only the last 10%... you gotta get the 90% right first!


Widget

Hi Widget,

In your view what is the 90%?

[Mr. Widget]

Hi Widget,

In your view what is the 90%?I think that depends on the listener.

For me it would be having a relatively linear FR, controlled off axis response, somewhat extended frequency range, and certainly dynamic capability. After maximizing all of those aspects of reproduction, I'd like to control phase, group delay, and the other aspects of time.


Widget

[Mr. Widget]

The promise of fidelity was launched in 1925 with recording's adoption of the electric microphone but that seminal landmark has rarely been fully capitalized on by subsequent developments.A bit off topic of this otherwise off topic discussion, but reading early reports from the dawn of high fidelity, it is surprising to read earnest reports of people hearing early recordings through very early examples of what Bell Labs and others were working with and being fooled by the recorded sounds... thinking they were listening to live music. Today, our best examples of recorded music and playback equipment are vastly more accurate and yet we are rarely fooled.

None of us are old enough to have firsthand experiences of these demonstrations but I do remember the first time I saw 480i video content through a Faroudja line quadrupler and a large CRT projector. I thought that I was seeing magic and that it was so close to watching a true film experience, I couldn't imagine it getting any better. By today's standards that image would make me cringe, but at the time it was magic!


Widget

[Ducatista47]

A bit off topic of this otherwise off topic discussion, but reading early reports from the dawn of high fidelity, it is surprising to read earnest reports of people hearing early recordings through very early examples of what Bell Labs and others were working with and being fooled by the recorded sounds... thinking they were listening to live music. Today, our best examples of recorded music and playback equipment are vastly more accurate and yet we are rarely fooled.

None of us are old enough to have firsthand experiences of these demonstrations but I do remember the first time I saw 480i video content through a Faroudja line quadrupler and a large CRT projector. I thought that I was seeing magic and that it was so close to watching a true film experience, I couldn't imagine it getting any better. By today's standards that image would make me cringe, but at the time it was magic!


Widget

Yes, and 4K video was described as like looking through a window. Truth be told, we don't even see in 4K.

I found the book Perfecting Sound Forever by Greg Milner a meaningful dive into what those early experiences were up to and how they did it. Its subtitle is "An Aural History of Recorded Music". David Byrne's book later covered a lot of the same territory but I find Milner's work to better describe what you are talking about. YMMV...

PS I reconsidered the post you have quoted and rendered it less rant-like. It now addresses this issue more directly.

[Ducatista47]

I think that depends on the listener.

Widget
Absolutely, or Plus 1 as it is said around here.

One comparison easy to make is to sample over time a really accomplished personal listening system. Experience perfect time alignment, zero room distortion, off axis response rendered moot, frequency response "In your dreams", phase and group delay issues absent, etc... It makes for a nicely calibrated zero point. No chest thump, a deal breaker for you I know, but for the rest a great yardstick.

[Ian Mackenzie]

I agree as well. Time alignment and phase coherence are greatly overrated. Frequency domain is much more important.

Rob :)

Hi Rob,

I was reading an article this afternoon (during the big wet season here) on loudspeaker design that stated the human ear (not an apes) is more sensitive to time domain or phase type anomalies at lower frequencies while more sensitive to amplitude anomalies at higher frequencies.

That could well be true. Although there are long held views that the human ear is most sensitive to time domain anomalies around 2000 hertz based on historical hearing tests. But of course we know that phase cancellation or peaks are what we hear around the crossover region when such anomalies occur.

[Ian Mackenzie]

I think that depends on the listener.

For me it would be having a relatively linear FR, controlled off axis response, somewhat extended frequency range, and certainly dynamic capability. After maximizing all of those aspects of reproduction, I'd like to control phase, group delay, and the other aspects of time.


Widget

When you refer to dynamic capability are to saying more dynamic than a Quad ESL or a Maggie?

Or are you referring to low power compression?

One of the problems that l think fools peoples view of time domain distortion is the rise and settling time of a driver diaphragm. Also diffraction related time smear.

Who recalls John Dunlavy? He did a lot of work in this area of loudspeaker design. His designs were generally well regarded.

It is perhaps little known that a Ribbon transducer performs poorly compared to a dynamic driver in this measurement parameter. Ribbons do not start or stop nearly as quickly. Some people like the aberrations of a Ribbon driver.

[Robh3606]

Hello Ian

They did integrate a CD Mantaray horn into the 604. I believe that Great Plains uses a similar of the same horn. Tangerine phase plug and so on so they were keeping "current" but I don't know the timing. If I remember right the time aligned URIE's were the real competition as far as coax's go. They used Altec drivers until they started having quality issues and ended up using all JBL with an E-145 and 2425 coax with a proprietary URIE/JBL horn in the final C versions.

I think they had lost market share or were in decline by the time the Mantaray and 4430 were introduced but I am not the historian so if you know please chime in.

1983 First I can find in the Library http://www.lansingheritage.org/html/altec/catalogs/1983-pro.htm

Check this out 1993! http://www.lansingheritage.org/html/altec/specs/pro-speakers/9864.htm

Rob :)

http://www.audioheritage.org/vbulletin/showthread.php?37387-Altec-model-18-with-the-604-8-H

http://www.lansingheritage.org/html/altec/specs/home-speakers/model-18.htm

[srm51555]

That said, I think it is obvious that absolute accuracy is not needed for musical enjoyment.


Widget

This is a very true and possibly expensive lesson.

[Ian Mackenzie]

Hi Rob,


I found the 604-8K spec sheet and your right. That was the 1992 spec.

The stock Altec network still has that characteristic bump at 1500 hz that the 4310 mimics.

The polar response for the 60x40 manta ray HF horn is very narrow. That in itself is obvious when you listen to that version. In comparison the 2307 /2308 is smoother and has a much better off axis response for a non cd design.

Off axis its awful and goes back to my earlier statement. What ever they were tried to do as a dual concentric idea it had lots of un resolved issues. But they didn't mind if it sucked.Those engineers must have been cloth eared old fucks.

Those Urei's of yours are way nicer loudspeaker.

Back in the day this was probably acceptable not in todays consumer market. I have no doubt the GP version is more refined but at US$1700 per driver it would want to be outstanding. Its the bees knee's for the SE triode guys because of the efficiency. But that's almost the waiting room end of the business where every recording sounds nice and engaging.

In this link is a far superior network ref Jeff Markwart’s Corner
This networks shifts the phase.

https://greatplainsaudio.com/gpa-vintage-altec-ezine/phase-correction-altec-ferrite-duplexes/

The Urei / Ed Long network was a multi stage Bessel filter that delayed the woofer for the 5 1/2 in offset.

[Mr. Widget]

Absolutely, or Plus 1 as it is said around here.

One comparison easy to make is to sample over time a really accomplished personal listening system. Experience perfect time alignment, zero room distortion, off axis response rendered moot, frequency response "In your dreams", phase and group delay issues absent, etc... It makes for a nicely calibrated zero point. No chest thump, a deal breaker for you I know, but for the rest a great yardstick.I was thinking of the technical advantages of headphone reproduction as I wrote that... however in addition to the lack of chest thump, real music is created in a room and travels through the air. With headphones, the music appears in the center of your head... an interesting way to experience music, but not for me.

Intimate jazz and other acoustic music works best in our homes. When listening to a symphonic recording in my living room there are certainly compromises of scale, but for me at least, I find it preferable to the sound being focused in the center of my head. True binaural recordings are a different case of course, but the source material is rather limited.


Widget

[Mr. Widget]

When you refer to dynamic capability are to saying more dynamic than a Quad ESL or a Maggie?

Or are you referring to low power compression?For many years my main 2 channel speakers were a pair of Soundlabs electrostats. The micro dynamic details were amazing, but the lack of macro dynamics due to power compression killed the "real musicness" for me. I think both micro and macro dynamics are needed. For me a 4" beryllium domed compression driver with appropriate supporting drivers gives the best compromise in the micro/macro dynamics department.


Widget

[Mr. Widget]

Remembering the vinyl era, we ancient ones often have to explain that we didn't even hear the pops and cracks. We learned to ignore them. Speakers are like that, if we let them be. Our brains know what music sounds like and it does a fine job of filling in the blanks both speakers and listening rooms get wrong, and tweaking towards reality.Not sure I could ever completely filter out the ticks and pops, but I get your point and agree completely about our personal onboard computer's ability to recalibrate the aural stimuli we call recoded playback. This is what allows us to hear music instead of analog screeches or dithered 1s and 0s.

Heck, we can even listen to an old transistor radio with a 3 inch "full range" speaker and still hear the music... pretty remarkable really.


Widget

[toddalin]

Because I have the ability to move the 2251 and Heil AMT relative to the 2241 and each other, I have found that time alignment can make a big difference in frequency response in the crossover region and based on the 61-band RTA, it could be on the order of several decibels. If one truly values a smooth and flat frequency response, this cannot be ignored.

Also, based on the RTA, and what I've read, it is not a matter of getting the voice coils in the same plane. Higher frequencies propagate faster and speakers may give a better, smoother response when stepped back a bit from what you would expect to be the plane. Ever looked at the impulse response in the Stereophile magazine for multi-way speakers? The signal from the tweeter, then mid, then woofer hit the mic in that order.

https://www.stereophile.com/content/measuring-loudspeakers-part-two-page-3

[Robh3606]

Because I have the ability to move the 2251 and Heil AMT relative to the 2241 and each other, I have found that time alignment can make a big difference in frequency response in the crossover region and based on the 61-band RTA, it could be on the order of several decibels. If one truly values a smooth and flat frequency response, this cannot be ignored.

Also, based on the RTA, and what I've read, it is not a matter of getting the voice coils in the same plane. Higher frequencies propagate faster and speakers may give a better, smoother response when stepped back a bit from what you would expect to be the plane. Ever looked at the impulse response in the Stereophile magazine for multi-way speakers? The signal from the tweeter, then mid, then woofer hit the mic in that order.

https://www.stereophile.com/content/measuring-loudspeakers-part-two-page-3

Hello Toddalin

Yes WRT moving the physical location of a driver. When you input driver parameters into LEAP as an example you have to enter the driver offsets. If you don't do that it assumes they are aligned and what you design will not match what you measure. As long as you put in the offsets properly what you design will match what you measure. When you are combining the response of 2 drivers you have to get this right to avoid irregularities through the crossover region as you noted on your RTA.

Rob :)

[Ian Mackenzie]

I could not agree more, I enjoy listening to 1930s recordings if the music is great.

Even so, I continue to be let down over how few music enthusiasts seek reproduction that attempts to follow as closely as possible what went into the microphone. You know, what the musicians actually did. As I have said before, it seems everyone has their favorite distortion; euphonics is the biggest flavor in high end audio. I have passed the point where speakers can come close enough to the truth to compete with what a modest personal listening system can do, so I have nothing to contribute anymore to speaker discussions. But I still like to hear what you guys have to say and report about it.

Since we now actually know how to record accurately and create media (streaming included) for home use that reflects that result, I do find it strange how much money and toil one will put into improving speakers, which will still have a couple of orders of magnitude more distortion than the electronics that drive them and at least another order of magnitude worse than the source material. If one is chasing perfection speakers are not a fitting tool to do it with. Playing music euphonically should not cost much. Simply accepting the shortcomings of the tools we enjoy anyway seems a more rewarding path than dwelling on the ways we wish they were better.

Remembering the vinyl era, we ancient ones often have to explain that we didn't even hear the pops and cracks. We learned to ignore them. Speakers are like that, if we let them be. Our brains know what music sounds like and it does a fine job of filling in the blanks both speakers and listening rooms get wrong, and tweaking towards reality.

Hi Clark,

I always find your posts interesting and entertaining.

But l do not entirely agree on everything you have said.(not to be taken too seriously please by anyone while the world is on the verge of war. Take your mind off it with this long post)

1. In your first paragraph you have not presented any arguments or evidence to support your sweeping statement concerning what music enthusiasts are seeking.

It may surprise you that musicians have the highest tolerance for interpretation or filling in the blanks in what reproduction of a recorded event has either missing or added. This is because they are by virtue of their training and understanding of music emotionally involved from the outset. Whereas the non musician listener needs to become emotionally involved and that therefore is the challenge of the equipment. This was explained in a document l read recently written by a trained pianist who has a PHD in material science and who was a senior loudspeaker designer for Linn Sondek before starting his own successful HiFi loudspeaker business. In his time at Linn his designs sold more than anything Linn had previously bought to market. You might ask why? The answer is this designer actually understands what a musical instrument sounds like and also what is actually required from a physics perspective of a loudspeaker driver which is a complex thing to get right. I actually own a pair of monitors designed by this scientist Dr Rod Crawford. He’s exhibited at the Rocky Mountain Audio Show on the past.

You might go oh l don’t agree with that and some musicians will say Ah that sounds close. But in fact very few hifi loudspeakers can come even remotely close to the live reproduction of a properly tuned piano. On the one hand it’s string instrument but it also has so much percussion to it’s sound.

Another acquaintance l know learnt the trumpet at high school and was taught by Ken Smith who at the time was one of best trumpet players in world. He has gone on to become the conductor of the Singapore symphony orchestra and has made similar remarks. He can put the recorded sound to one side without a problem because he already he knows exactly what every instrument does sound like.

Where it goes pear shaped is when the consumer with deep pockets is misled into believing what hifi sound reproduction really is by certain factions of the hifi industry. If you look at the statistics not much hi end bubblegum audio is actually sold because most of us can’t afford it. That’s a good thing. (Leave it to the Dentists). That’s because it’s made and sold by people who are only interested in lining their pockets. There are a stack of them in the USA and you’ll find them in Stereophile Magazine. I call it the HiFi Mafia made up of micro manufacturers with tentacles everywhere.

https://www.britannica.com/story/is-the-piano-a-percussion-or-a-stringed-instrument

General speaking the reproduction of the piano is regarded as true test of a hi fidelity sound system.

2. Secondly, my view is that your second paragraph is a little too broad because frankly we have not yet reached a point of strong consistency in recording standards despite the technological advances. Next to the loudspeaker and a room’s impact on sound reproduction l strongly believe that recordings of the same piece or tune can vary considerably in terms of quality of reproduction across different editions and labels. I find that rather annoying. Imagine if car today were built this way? The Jeep motor company is the exception. They are rubbish.

I personally believe that relatively low cost consumer hifi loudspeakers have improved considerably over the past 25 years. Distortion levels in modern loudspeaker drivers has come down with advanced technologies in materials, design and manufacturing techniques. Certainly there is a law of diminishing returns but that goes for anything that is categorised as a luxury item. I think cost often relates to the scale or power of a loudspeaker system. The bigger, louder, lower and higher it goes with low distortion the price rockets. Typically into six figures. If you take a Wilson system for example they are recognised standard and they are not cheap.

[Ducatista47]

Not sure I could ever completely filter out the ticks and pops, but I get your point and agree completely about our personal onboard computer's ability to recalibrate the aural stimuli we call recoded playback. This is what allows us to hear music instead of analog screeches or dithered 1s and 0s.

Heck, we can even listen to an old transistor radio with a 3 inch "full range" speaker and still hear the music... pretty remarkable really.

Widget
I could rephrase a little and say that I could hear the vinyl noise if I thought about it, but listening to music took my full aural attention and it was not within my realm of consciousness. I have very mild tinnitus and I never hear it unless I read "tinnitus" or someone mentions it in conversation. It was like that, so when hearing music on vinyl I really didn't notice it in the least.

[Mr. Widget]

Hi Rob,


I found the 604-8K spec sheet and your right. That was the 1992 spec.

The stock Altec network still has that characteristic bump at 1500 hz that the 4310 mimics...I stumbled on this review from Audio Magazine of the AR LST 1 "studio monitor".

"Summing up, the AR LST must be considered one of the best speaker systems now available. If only some of our recording studios can be persuaded to use them in preference to the "presence-peaked" monitors, maybe record quality would improve.
-T.A. & G.W.T.
(Audio magazine, Dec. 1972)"

Reading that line made me think of this thread.

Widget

[Ian Mackenzie]

Well l don’t know about you but after l built my 4343’s in the early 80’s l reckon l could l could tell which recordings were mixed on JBL. They sounded more balanced and the bass was better.

Some of my local bands were mixed Tannoys and they were also good.

Around that time a number of large studios were being designed by Tom Hidley and my impression is recording studios lifted their game and recording got better.

http://www.muzines.co.uk/articles/tom-hidley-studio-designer/1649

https://www.acousticfields.com/tom-hidley-non-environment-rooms/

https://www.audiotechnology.com/PDF/REGULARS/NAME_BEHIND_THE_NAME/AT37_NBN_Tom_Hidley.pdf

[speakerdave]

Uh huh. I would be interested to know exactly what you were hearing that was out of balance and in what direction. That is, by inference, what exactly you are inferring the reviewer meant was the effect of studios using "presence-peaked" monitors.

[toddalin]

Uh huh. I would be interested to know exactly what you were hearing that was out of balance and in what direction. That is, by inference, what exactly you are inferring the reviewer meant was the effect of studios using "presence-peaked" monitors.

Probably the signiture of the horn that can't be helped except with eq.

[toddalin]

Well l don’t know about you but after l built my 4343’s in the early 80’s l reckon l could l could tell which recordings were mixed on JBL. They sounded more balanced and the bass was better.




If you listen to Ambrosia, they recorded at Momma Jo's studio in North Hollywood on Altec Super Reds. We had rented the studio right after them and some of the equipment was still inplace (e.g., Baldwin electric harpsichord). This was my first exposure to the Super Reds and boy was I impressed.

https://en.wikipedia.org/wiki/Ambrosia_(band)


https://www.dailymotion.com/video/x23duhz
https://www.dailymotion.com/video/x23duhz

[Robh3606]

If you listen to Ambrosia, they recorded at Momma Jo's studio in North Hollywood on Altec Super Reds. We had rented the studio right after them and some of the equipment was still inplace (e.g., Baldwin electric harpsichord). This was my first exposure to the Super Reds and boy was I impressed.

https://en.wikipedia.org/wiki/Ambrosia_(band)


https://www.dailymotion.com/video/x23duhz
https://www.dailymotion.com/video/x23duhz


Don't for get who produced it Alan Parsons. Always liked that album!

Rob :)

[Ian Mackenzie]

I stumbled on this review from Audio Magazine of the AR LST 1 "studio monitor".

"Summing up, the AR LST must be considered one of the best speaker systems now available. If only some of our recording studios can be persuaded to use them in preference to the "presence-peaked" monitors, maybe record quality would improve.
-T.A. & G.W.T.
(Audio magazine, Dec. 1972)"

Reading that line made me think of this thread.

Widget

Hi Mr Widget,

I do recall those AR LST models. As l recall they were well regarded acoustic suspension design but inefficient. Not cheap at the time either.

On the other side of the Atlantic the BBC were developing small bookshelf monitors and B&W were starting to make inroads into the studio business. UK Studio builders like Reflection Arts were designing high powered 3/4 way dual 12” and quad 12” woofer systems using the 2123H midrange, a 2” Dynaudio dome upper midrange and 1 “ Dynaudio dome tweeter. Quested were also offering similar monitors.

By similarity they were a high powered AR LST.

So globally l don’t think Altec had a caveat on the monitor business overall. In a certain time period like from mid 40’s to the late 60’s l have no doubt some biased US historians in the USA have the story right on the 604’s.

But as Tom Hidley points out the studio business was evolving very quickly and it was a time of a word of mouth development. There was no www or email. Only those black phones. So l think some of what went on was quite regional in terms of preferences.

The more serious players who could obtain finance had the likes of Tom Hidley design and build the whole package.

On reflection (sorry) the 604’s would be lucky to get 50 hertz or anything below that at high power levels before exceeding their 4mm X max. Hence the dual helper woofer idea came into vogue with those huge Urei monitors and the JBL 4435.

The quest for more accurate mixing of frequencies at 40 hertz and below with more advanced studios and monitors was certainly on the radar even in the vinyl era. This supports my comments that “some” imported pressing on certain labels had obviously deeper, lower and louder bass reproduction.

If you were wealthy and owned RTR magnums or something really exotic loud like transmission lines then loud low bass in a domestic home situation was a privilege. My diy bi amped 4343 clone at the time was a freak of nature. At one point l a had dual 2231H drivers per channel.

With the 604’s in older designed studios the producer and engineer couldn’t mix what they couldn’t hear not that they cared. The 2235H in comparison was an extended bass woofer and with correct soffit mounting was a more linear and accurate LF transducer. JBL as l recall developed the 2230 for the 4350 and was a departure from the LE15A. It evolved into the 2235H. That 15 inch woofer became the de facto woofer in a number of JBL systems and custom monitors for a long time. Tad were in there but it was perhaps the upmarket alternative.

For the SET HiFi brigade the 604 is an interesting option. But like with 5 watts or up to 12 watts there’s not to many full range loudspeaker with that kind of efficiency. The Lowthers were ten times more unbearable than the stock 604’s imho.

[Robh3606]

AR-LST Sensitivity is very low about 82 db 1 watt 1 meter. Power handling is also low. I remember when these first came out back in the day. Don't think I ever got to hear a pair. With the sensitivity and low power handling definitely not a "rock" monitor.

Rob :)

[Robh3606]

The quest for more accurate mixing of frequencies at 40 hertz and below with more advanced studios and monitors was certainly on the radar even in the vinyl era. This supports my comments that “some” imported pressing on certain labels had obviously deeper, lower and louder bass reproduction.

Anyone know what Telarc used for monitors?? Just thinking of their 1812 and Pictures at an Exposition. Talk about bass response!!

Rob :)

Found it they used ADS BC-8/11 Monitors.

[rusty jefferson]

I stumbled on this review from Audio Magazine of the AR LST 1 "studio monitor".

Widget
That's a speaker I'm not familiar with. I appreciate that it has good off axis response, though I'd like to see 15 and 30 degrees also, as there could be lobing issues. I'm also not sure why he'd make the case for using them as studio monitors. The side mounted mids/tweeters are going to cause all kinds of early reflection issues in a typical small control room, and there has to be time domain issues with the design. They seem appropriate for the living room.

Also, I just spent a good part of the day listening to a radio show of the American Songbook. Peaked or not, some of the finest recordings made including greats like Ella Fitzgerald, Sarah Vaughan, Blossom Dearie, Nat King Cole, and Sinatra were probably made using 604s in a plywood box. They were simple recordings and sound terrific by any measure, even by today's standard. The trouble didn't start until multi-tracking, Dolby, compressors, EQ, overdubbing and a multitude of other crap made its way into the control room.

I do have a preference for the time aligned UREI monitors compared to the standard 604s. They are more coherent. Never heard the model Todd has but if it functions equivalently to the UREI crossover, it should be an improvement and equal to the early UREIs that used the 604.

[Ian Mackenzie]

I think it’s all relative.

Some of the early recording techniques were “pure” with just two mics and a mobile control room.

But it’s the LF bandwidth and higher SPL l was referring to. In the earlier studios/ control rooms that wasn’t fully considered.

Back in the day a lot of advertising said the HiFi Sound Reproduction was from 20 to 20,000 hertz. But the 1st octave was not monitored or considered. A lot of those higher sensitivity systems back then were tuned to 45 hertz which meant they were -3 at 49-55 hertz or higher.

In contrast the introduction of the 2230 drivers in the 4350 signalled much lower box tuning at 30 hertz opening up higher power handling down to 30 hertz. I have heard and compared a JBL 2220 driver to a similar system with a 2231A and it’s night and day. It’s those lower frequencies that add what’s missing to a what might be termed low frequency linearity. A 604 will sound louder with the volume up. The 2231A will sound bigger and louder.

[Ian Mackenzie]

If your wondering l am giving the 604’s a flogging.

[Ian Mackenzie]

AR-LST Sensitivity is very low about 82 db 1 watt 1 meter. Power handling is also low. I remember when these first came out back in the day. Don't think I ever got to hear a pair. With the sensitivity and low power handling definitely not a "rock" monitor.

Rob :)

Hey Rob

Those LST systems were not DC coupled. Check out the return path to the input terminals.
I suspect they used a high compliance woofer that would easily bottom with turn on/off thumps and those high capacitor values offered some immunity to that and turntable rumble.

[Mr. Widget]

That's a speaker I'm not familiar with. I appreciate that it has good off axis response, though I'd like to see 15 and 30 degrees also, as there could be lobing issues. I'm also not sure why he'd make the case for using them as studio monitors. The side mounted mids/tweeters are going to cause all kinds of early reflection issues in a typical small control room, and there has to be time domain issues with the design. They seem appropriate for the living room.Realize that review was in 1972. We have come a long way since then.

These speakers are essentially clones of the famous AR3a with added tweeters and mids. Obviously the geometry is different as well, but back in the late '60s and early '70s the AR3a was considered one of the finest speakers by most listeners with the main criticism that it was a bit rolled off and polite up top. I imagine adding a second mid and three more tweeters brought up the top end.


Widget

[Mr. Widget]

Also, I just spent a good part of the day listening to a radio show of the American Songbook. Peaked or not, some of the finest recordings made including greats like Ella Fitzgerald, Sarah Vaughan, Blossom Dearie, Nat King Cole, and Sinatra were probably made using 604s in a plywood box. They were simple recordings and sound terrific by any measure, even by today's standard. The trouble didn't start until multi-tracking, Dolby, compressors, EQ, overdubbing and a multitude of other crap made its way into the control room.
No argument from me. There were plenty of great recordings made back in the pre multi-tracking days.


I do have a preference for the time aligned UREI monitors compared to the standard 604s. They are more coherent. Never heard the model Todd has but if it functions equivalently to the UREI crossover, it should be an improvement and equal to the early UREIs that used the 604.I think most of us would agree with that... I am not sure if the improvements were with the "time alignment" or the EQ, but regardless, the Ureis were exceptional speakers in their day and still don't suck.


Widget

[Ian Mackenzie]

Probably the signiture of the horn that can't be helped except with eq.

Hi Todd,

Looking at Don’s historical profile of the 604 and the Mastering Lab crossover the problems with the horn were the peakiness.

But the peaking was due to limitations of the original horn profile and the abrupt acoustic impedance termination at the mouth of the horn. What Ed Long did you was to add carefully grades of acoustic foam strategically to the horn that minimised shadowing with the woofer cone while also extension the acoustic length of mouth with the foam moulding. Electrical EQ might have reduced the problem but not removed the cause. I can vouch that your 604’s were more listenable than the stock 604’s and l have heard Rob’s centre channel Urei which some subjectively is a different loudspeaker by comparison.

Had Doug Sax not yet Carolyn invested in his idea the Urei monitors would not exist. At least that’s my impression from that story.

[toddalin]

No argument from me. There were plenty of great recordings made back in the pre multi-tracking days.

I think most of us would agree with that... I am not sure if the improvements were with the "time alignment" or the EQ, but regardless, the Ureis were exceptional speakers in their day and still don't suck.


Widget


Here you go! After all, this is LA.

https://images.craigslist.org/00C0C_cPj6oZDXhy5z_0fu0bC_1200x900.jpg
https://images.craigslist.org/01313_eQNye8sJ6Phz_0fu0bC_1200x900.jpg

https://losangeles.craigslist.org/lgb/ele/d/long-beach-speakers-urei-811-monitors/7455401131.html

[rusty jefferson]

"I Love L.A.!"

[hjames]

"I Love L.A.!"


"I Love UREI!"

(got 2 pairs of 809As ...plus a 3rd pair of spare drivers)

[eso]

Here you go! After all, this is LA.

https://images.craigslist.org/00C0C_cPj6oZDXhy5z_0fu0bC_1200x900.jpg
https://images.craigslist.org/01313_eQNye8sJ6Phz_0fu0bC_1200x900.jpg

https://losangeles.craigslist.org/lgb/ele/d/long-beach-speakers-urei-811-monitors/7455401131.html

Those were assembled using cabinets from a pair of 811A that I stumbled across. These are headed to a new analog studio outside of Nashville.

Meanwhile the ferrite 604 8K/801AA duplex drivers have become these floor standing speakers. All of the caps in both sections of the networks were replaced with NOS Soviet era PIO caps and I charge-coupled the HF section. Fresh GPA recones installed by edgewound (I think that's Ken's handle here) They are a fine sounding pair

90341